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Table of Contents
Year : 2019  |  Volume : 10  |  Issue : 1  |  Page : 52-53

“Boomerang sign” in dengue encephalitis

1 Department of Medicine, Jawaharlal Nehru Medical College, DMIMS University, Wardha, Maharashtra, India
2 Department of Pathology, Jawaharlal Nehru Medical College, DMIMS University, Wardha, Maharashtra, India

Date of Submission30-Jan-2019
Date of Acceptance31-Jan-2019
Date of Web Publication18-Feb-2019

Correspondence Address:
Dr. Priyansh Bhayani
Department of Medicine, DMIMS University, Jawaharlal Nehru Medical College, Sawangi, Meghe, Wardha - 442 001, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/INJMS.INJMS_6_19

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How to cite this article:
Bhayani P, Acharya S, Shukla S. “Boomerang sign” in dengue encephalitis. Indian J Med Spec 2019;10:52-3

How to cite this URL:
Bhayani P, Acharya S, Shukla S. “Boomerang sign” in dengue encephalitis. Indian J Med Spec [serial online] 2019 [cited 2023 Jun 7];10:52-3. Available from: http://www.ijms.in/text.asp?2019/10/1/52/252478


A 16-year-old female came with complaints of fever for 7 days. On the 6th day of fever, she presented with diplopia and headache. She presented to us with altered sensorium. On examination, she was febrile (100° F), pulse rate of 120 beats/min, and blood pressure 90/60 mmHg. On neurological examination, she had altered sensorium, Glasgow Coma Scale score 10/15, right lateral rectus palsy, and bilateral nystagmus, and Kernig's sign was positive. On abdominal examination, spleen was palpable 4 cm from the left costal margin. Other system examinations were normal.

Cerebrospinal fluid examination was within normal limits. Blood tests for malaria and leptospirosis were negative. Weil–Felix reaction was negative. Dengue immunoglobulin M antibody was positive.

A contrast magnetic resonance imaging of the brain revealed nonenhancing localized restricted diffusion in the splenium part of the corpus callosum on diffusion-weighted imaging, resembling “boomerang sign” [Figure 1]. The patient was managed conservatively which resulted in complete resolution of the sign in 2 weeks.
Figure 1: Diffusion-weighted imaging showing boomerang sign

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  Discussion Top

Transient splenial hyperintensity (TSH) can be noted in multiple conditions, as mentioned in [Table 1].[1],[2] Dengue encephalitis as a cause of TSH has not been reported in literature. TSH usually presents as one of two characteristic patterns, being either a well-demarcated, oval lesion in the midline within the corpus callosum or a more diffuse, irregular lesion extending throughout the splenium and involving the adjacent hemispheres. The proposed mechanisms implicated include a temporary breakdown of the blood–brain barrier, extrapontine myelinolysis, intramyelinic edema due to inflammation leading to microvascular endothelial injury, direct viral invasion of neurons, and toxicity or hypersensitivity to antiepileptic drugs.[3] The boomerang sign may denote a nonspecific brain injury since its clinical significance is not clear yet. These signs are reversible and disappear within a few weeks. The exact reason for increased predilection of the splenium of the corpus callosum is still not known.
Table 1: Differential diagnosis for transient splenial hyperintensity

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Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Doherty MJ, Jayadev S, Watson NF, Konchada RS, Hallam DK. Clinical implications of splenium magnetic resonance imaging signal changes. Arch Neurol 2005;62:433-7.  Back to cited text no. 1
Malhotra HS, Garg RK, Vidhate MR, Sharma PK. Boomerang sign: Clinical significance of transient lesion in splenium of corpus callosum. Ann Indian AcadNeurol 2012;15:151-7.  Back to cited text no. 2
Bulakbasi N, Kocaoglu M, Tayfun C, Ucoz T. Transient splenial lesion of the corpus callosum in clinically mild influenza-associated encephalitis/encephalopathy. AJNR Am J Neuroradiol 2006;27:1983-6.  Back to cited text no. 3


  [Figure 1]

  [Table 1]


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